I hope to have a youtube video up sometime today doing a semi scientific test, we shall see

I have a few different seven string guitars in 3 different scale lengths, a 25.5″, a 27″ and a 28.625″. I tune the regular six strings to standard six string tuning, and the lowest seventh string to drop A

Usually when you are tuning lower with everything else being equal, the low tuned strings will be floppy, and often buzzy, requiring higher height above the fretboard (action) to avoid really bad buzzing

The solution to this problem is in conventional wisdom, to change the size of the string until it has equal tension to the tuning it would have normally been in, or just more tension in general. There are several competing schools of thought, like even tension, progressive tension, and just whatever the hell tension the guitar string makers decide to throw in packs.

I have been slowly going higher and higher in size on my seventh string to the point where I am putting what many would call bass strings on my guitar.

On my 27″ for instance, in order to get that low A to the 16 pounds of tension of the low E above it on the sixth string, that requires a size 64 string, instead of the 52 that this particular seven string pack comes with. Even to get to the 13 pounds that string would be at in standard B tuning, I’m looking at a size 58 string.

The claim that people make is, a string with higher tension will have a smaller elipse, thereby needing less action height to clear the frets and keep from buzzing.

Bear in mind that the way the strings contact the instrument, all else being equal, the distance between the frets and the BOTTOM of the string remain constant, regardless of the string size. (By all else being equal, I mean taking into account the bow of the neck changing with changing string tension and a few other factors)

Only the distance between the top of the frets and the TOP of the string changes with string size.

On a whim, after being really frustrated by one of the guitars, with even a size 70 string on it, I went and stuck the 56 that came with the package on and tried it. It buzzed LESS! I figured I was in error, so I stuck the big string on, recorded a direct input of the guitar in various different types of playing and then did the same with the 56.

The 56 most certainly did buzz far less, and could have a much lower action before becoming intolerable. It feels like spaghetti and weird, but it performs sonically so much better.

What the hell is going on here? Shouldnt the bigger string with more tension have a smaller elipse and buzz less? Shouldn’t the smaller string with much less tension (11 pounds vs 17 pounds) be the far worse performer?

I often drive myself NUTS with audio questions and get into analyisis paralysis and can’t actually get work done. What the hell is happening?

Assume the setup is correct, I’ve been up and down all of these with fret rockers, levelling files and crowning files. Truss rod is adjusted correctly as the string tensions change. In fact, if anything, after I put the smaller strings on and the neck backbowed, it should have been MUCH MUCH worse than the larger string, but it wasn’t, it was far superior.

Offhand, revisit your assumptions about the endpoints and the string, and the geometry of the ellipse. It probably makes the most sense to think of the endpoints of the ellipse as being located at the centre of the string’s core at the point where the string breaks over the bridge saddle or the nut. So for an “ideal” string of zero thickness, the endpoints of the ellipse are at a height of zero above the surface of the nut slot or saddle, but for a string of diameter “d”, the endpoints of the ellipse are at a height of d/2 above the nut slot or saddle. Work out the maximum amplitude at the midpoint of a the string strung between the two d/2 endpoints in terms of the zero thickness line at the core of the string, then add d/2 to that amplitude (for the string thickness) to get the full distance from string center at d/2 above the nut to string bottom at the midpoint.

It’s also might be possible that the ellipse formed by a thicker string could be distorted (pointier at the ends) than the ellipse formed by a thinner string.

WOuldn’t it still be only the top of the string to the fretboard height that changes with string size?

Possibly. I’m just spitballin’. 😉

Are you keeping the amplitude of the standing wave constant, or the force applied with the pick constant? A thicker string will require more force to get the same amplitude.

Edit: Since you’re talking about differences in ellipse size, I guess that means your talking about keeping the the force applied with the pick constant, but how are you controlling/measuring that?

Edit 2: I guess the mechanics of picking are such that the crucial variable is how far the pick displaces the string at the point where the picking occurs (maxium displacement before the pick “releases”). Same question stands, how is that being controlled/measured?

I think you’d have to do this test on guitars with zero fret too right.

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Oh haha, this gets into Physics, my specialty. So with respect to string thickness vs tension vs tone, let’s take a look at some initial facts:

Thicker strings require more tension than thin strings to make the same pitch (note) when vibrating.

If two strings of different size have the same tension, the thicker string will be more floppy.

Knowing this, and your experimental results, there is not an exactly linear relationship between string thickness, string tension, and pitch with regards to vibrating.

So just because your thicker string has more tension to produce the same pitch note as the thinner string, doesn’t mean that it’ll be less floppy. The relationship of tone and string tension is not exactly proportional to string tone and string thickness.

Think of this scenario:

Tie a really thin rope tightly between two trees and see how much it vibrates. It should be pretty taught.

Then tie a really thick rope between two trees as tight as you can. You can tie super super tight, but the thick rope won’t be as taught as the thinner string when plucked.

All in all, we can know this:

Higher string tension won’t mean less flop in a thicker string whose thickness is outside the threshold of relationship proportionality.

Did you take in account for string manufacturer’s differences in core thickness and also core type?
For example, GHS boomers tho being a round core is a lot thicker by default than standard company strings (even comparing similar round cores) and is similar tension to a gauge up.

The hex cores I’ve researched that the ratio makes them much more tense than round cores, but then you gotta factor in how thick is the hex core? If a round core of string A is twice the size of the hex core on string B, then it would probably be equal.

But what if the hex core is 3/4 as thick? Then it’s actually TENSER at the same gauge. Things like this you can’t really find out online as they brand doesn’t specify. Btw, I’m not so sure about 1/2 or 3/4. This is just an example. I can’t get some clarity from the sites right now. I just know the Hex ratio is much tenser and requires less.

I would love love love to know more about different tensions between different string manufacturers. I really was confused if different tension at the same size and tuning was even possible. I’d LOVE to have a 56 with the same tension as a 70!

http://www.ghsstrings.com/products?categories=thick-core-boomers
For people with Kahler hybrid tremolos, the highest string that goes in there is a .046 so getting a thick core would help until one would upgrade the trem.
That’s why a friend handed me his guitar with 10’s and I wondered why I felt like my 9s.. (back before core sizes weren’t advertised)

I just got these strings, but I have no idea how much tension they will have.